I am struggling to find the glass transition temperature of poly(proylene glycol-400) dimethacrylate, PPG(400)DMA.
If anyone knows where I could find this, or knows of a method to accurately estimate this, please let me know.
Dear Nick J Walters
DSC or TGA are the two appropriate instrumental techniques which are used to find Tg, Tm and all types of thermal analysis.
DSC will be most appropriate to find Tg of your sample.
regards
shakeel
Thank you Shakeel for your advice. If possible, I am looking to find this out from the literature rather than by having to measure it. If anyone knows the value, I'd be grateful for advice. Otherwise, I will look into using DSC.
Glass transition is a second order phase transition where specific heat and many other physical properties change at glass transition temperature. As it is difficult to find out this temperature by measuring theses properties as a function of temperature, thermo analytical analysis is most suitable method to find out this temperature in glasses and polymers. Since DSC is more sensitive than DTA , DSC can be used for polymers as glass transition temperature is not very high in polymers. Perform DSC at lowest heating rate as glass transition temperature is found to be higher at higher heating rates in glasses and may be in polymers also. Take care of this fact.
I am sorry, but glass transition is not a phase transition of neither first order nor second order. It is transition of the glass-forming system between two states: non-equilibrium state (glass) and equilibrium (metastable liquid) one.
Dear Dr Tagantsev
Your concept on glass transition temperature is O. K. The understanding of glass transition is still not complete. However, I would like to mention that according to modern concept of phase transition, glass transition is considered under the classification of second order phase transition as specific heat changes suddenly at glass transition. This is even mentioned in Wikipedia on phase transition under the heading classification.
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